1. Field of the Invention
The present invention relates to an antenna system, and in particular to a slip joint polarizer integrated into an antenna reflector system.
2. Description of Related Art
Recently, Very Small Aperture Terminal (VSAT) antenna systems are coming into widespread use in private communication systems. In such antenna systems a transmitter radio is fixedly connected via an ortho mode transducer (OMT) to a feed horn placed in front of a reflector. The antenna assembly including the transmitter radio, OMT, and feed horn is supported on the end of a boom. During installation the antenna assembly is rotated to adjust receive and/or transmit polarity of the side port and through port of the OMT based on the geographical site of the antenna relative to the satellite. Due to its relatively large size and weight, rotation of the antenna assembly is obtrusive and clumsy.
Instead of rotating the feed horn/OMT/transmitter radio assembly, some antenna systems rotate the entire reflector antenna system. In these antenna systems it is practical to rotate the entire antenna due to their relatively small size. Even so, such antenna systems require a relatively complex and expensive reflector back structure and a boom/feed support system that is able to withstand gravitational loads in many orientations.
Channel Master, the assignee of the present invention, has developed a probe polarizer in which a probe and its dielectric holder rotate while the feed horn, OMT and transmitter radio remain stationary. This construction, however, is very sensitive to manufacturing variations and requires a special fixture to set the proper angle of the probe. In addition, the probe is only used to adjust transmit polarity and has no effect on receive polarity.
It is therefore desirable to develop a relatively simple and inexpensive connection means for adjusting receive and/or transmit polarity of a linear polarity transmit/receive system that overcomes these problems.